"The book in question is The Total Rush – or, to use its superior English title, Blitzed – which reveals the astonishing and hitherto largely untold story of the Third Reich’s relationship with drugs, including cocaine, heroin, morphine and, above all, methamphetamines (aka crystal meth), and of their effect not only on Hitler’s final days – the Führer, by Ohler’s account, was an absolute junkie with ruined veins by the time he retreated to the last of his bunkers – but on the Wehrmacht’s successful invasion of France in 1940."

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"At a company called Temmler in Berlin, Dr Fritz Hauschild, its head chemist, inspired by the successful use of the American amphetamine Benzedrine at the 1936 Olympic Games, began trying to develop his own wonder drug – and a year later, he patented the first German methyl-amphetamine. Pervitin, as it was known, quickly became a sensation, used as a confidence booster and performance enhancer by everyone from secretaries to actors to train drivers (initially, it could be bought without prescription). It even made its way into confectionery. “Hildebrand chocolates are always a delight,” went the slogan. Women were recommended to eat two or three, after which they would be able to get through their housework in no time at all – with the added bonus that they would also lose weight, given the deleterious effect Pervitin had on the appetite. Ohler describes it as National Socialism in pill form."

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"But the invasion of France was made possible by the drugs. No drugs, no invasion. When Hitler heard about the plan to invade through Ardennes, he loved it [the allies were massed in northern Belgium]. But the high command said: it’s not possible, at night we have to rest, and they [the allies] will retreat and we will be stuck in the mountains. But then the stimulant decree was released, and that enabled them to stay awake for three days and three nights. Rommel [who then led one of the panzer divisions] and all those tank commanders were high – and without the tanks, they certainly wouldn’t have won.”

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https://www.theguardian.com/books/2016/sep/25/blitzed-norman-ohler-adolf-hitler-nazi-drug-abuse-interview